On Mon, Jan 06, 2025 at 03:47:43PM +0800, Ma Ke wrote:

Once device_register() failed, we should call put_device() to decrement reference count for cleanup. Or it could cause memory leak.

device_register() includes device_add(). As comment of device_add() says, 'if device_add() succeeds, you should call device_del() when you want to get rid of it. If device_add() has not succeeded, use only put_device() to drop the reference count'.

Found by code review.

Cc: stable@vger.kernel.org Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Ma Ke make24@iscas.ac.cn

---

Changes in v2:

• modified the patch as suggestions.

---

arch/arm/common/locomo.c | 2 ++ 1 file changed, 2 insertions(+)

diff --git a/arch/arm/common/locomo.c b/arch/arm/common/locomo.c index 309b74783468..9e48cbb2568e 100644 --- a/arch/arm/common/locomo.c +++ b/arch/arm/common/locomo.c @@ -253,6 +253,8 @@ locomo_init_one_child(struct locomo *lchip, struct locomo_dev_info *info) ret = device_register(&dev->dev); if (ret) {

• put_device(&dev->dev);
  

• return ret;
  

  out: kfree(dev); }

This makes the code layout quite horrible.

Instead, I suggest:

dev = kzalloc(sizeof(...)... - if (!dev) { - ret = -ENOMEM; - goto out; - } + if (!dev) + return -ENOMEM;

...

ret = device_register(&dev->dev); - if (ret) { - out: - kfree(dev); - } + if (ret) + put_device(&dev->dev);

Thanks.